1. Field of the Invention
The present invention relates to a power source circuit which is suitable for use with an electric discharge machine for cutting a workpiece by a discharge produced between an electrode and the workpiece.
2. Description of the Prior Art
In the case of the electric discharge machining of a workpiece through utilization of the discharge energy of a capacitor which is charged by a power source via a transistor or like switching element, when an arc forms between the electrode and the workpiece, the working efficiency drops and the worked surface is apt to be roughened. Such an arc, though not leading to a long-term, steady arc, often occurs momentarily under ordinary working conditions, thereby markedly impairing the working efficiency. To avoid this, it is desirable to eliminate an arc immediately when it develops, but prior art power sources for electric discharge machining are not provided with proper means therefor and hence they have the defect of poor working efficiency.